1. Field of the Invention
The present invention relates to an air conditioning system installed in a large-scale building or the like, and a controller for the air conditioning system.
2. Description of the Related Art
There are generally known an air conditioning system in which an outdoor unit and plural indoor units are connected to one another through an inter-unit pipe comprising a high-pressure gas pipe, a low pressure gas pipe and a liquid pipe so that the plural indoor units can perform cooling operation or heating operation at the same time (hereinafter referred to as “2-way air conditioning system”), and also an air conditioning system in which both heating operation and cooling operation can be performed in a mixing style (hereinafter referred to as “3-way air conditioning system”) (see Japanese Patent No. 2,804,527.
In a relatively large-scale building such as a commercial building, a hospital or the like, a large number of air conditioning systems as described above are used in combination because the number of rooms is increased, thereby constructing a large-scale air conditioning system having several hundreds to one thousand or more (hereinafter referred to as “multiple air conditioning system for buildings”) to air-condition each room in the building.
The switching operation between the cooling operation and the heating operation is carried out every outdoor unit in the 2-way air conditioning system and every indoor unit in the 3-way air conditioning system. Therefore, it is impossible to switch the air conditioning operations of the respective rooms in the building all together at the turn of the seasons or the like.